Background:The incidence of obesity in females ≥15 years of age in Egypt is one of the highest all over the world (33%)we investigated the impact of increased BMI on breast cancer incidence and survival. Methods:we reviewed files for 1873 female patients with breast cancer, presented at ACOD, from Jan. 1996 to Dec. 2005. , only 907 were eligible BMI of every patient was calculated and four groups were formed.The duration of follow-up was calculated from the date of registration to the date of death or last follow-up. The locoregional control period was between the end of treatment and failure of local control at 5 years or death or last follow-up OS was measured as the interval between the beginning of treatment and death or last follow-up evaluation. Results: patients were classified into 4 groups, the first group included 100 patients of BMI less than 18.5, the second group including 299 patients of BMI more than or equal to 18.5 and less than 25, the third group including 336 patients of BMI more than or equal to 25 and less than 30, and the fourth group including 172 patients of BMI more than 30. the highest peak of breast cancer incidence was in the age group 55-65 years (32.4%), while the lowest incidence was in the age group more than 65 (8.6%). Obese patients had the tendency to have breast cancer in younger age than normal weight patients with a mean of 38.6 years vs. 58.6 years. results showed that over weight patients constituted more than 37% while obese patients only constituted 19 %, normal weight 33% and underweight 11%. In our study, the majority of cases were staged as stage II and III (42.6 and 45.9 % respectively). Only 10.2% of patients in our series were recorded with stage IV; most of them were obese.Patients with increased BMI, in our study, had a significantly lower DFS ( p < 0.013).there was a statistically significant correlation between overall survival and BMI of patients (p=0.0015); there was an increase in mortality with increasing BMI. Conclusions: Our results report an increase in the incidence of breast cancer in overweight and obese patients in our population. Patients with high BMI were diagnosed at younger age, had more advanced stage and a statistically significant lower DFS & OS as compared to normal weight patients.